[Pc_Support] RE: RAID options for SATA -- XFX = NetCell RAID-XL

[Bryan J. Smith <b.j.smith at ieee.org>]

From: Damien McKenna <dmckenna at thelimucompany.com>
> http://www.xfxforce.com/web/product/listConfigurationDetails.jspa
> ?productConfigurationId=1091~$200.

That's the NetCell RAID-XL I was talking about.
ASIC takes 32-bit or 64-bit wide transfers and pushes them directly
to 2x 16-bit ATA or 4x 16-bit ATA, and then real-time XOR calculates
the 3rd or 5th disk on-card.

> By Christmas there should be more PCI-Express cards.

Personally, I'm waiting for this sucker to come out in end-user cards:  
http://www.broadcom.com/products/Enterprise-Small-Office/Storage-Solutions/BCM8603  

> RAID-3 looks pretty reasonable.  Not quite as fault-tolerant or
> flexible as RAID-5 but significantly cheaper.

???
RAID-3, RAID-4 and RAID-5 _all_ have the same level of fault-tolerance.
Lose 1 disk = okay.
Lose 2 disks = bad day.

RAID-3 and RAID-4 merely use a dedicated parity disk, instead of
striping the parity.

RAID-3 is geared towards desktops.
NetCell's RAID-XL is a variant of RAID-3.

RAID-4 is geared towards large file servers.
NetApp (and I agree with them) believes RAID-4 is much, much
better than RAID-5 for file servers -- especially for NFS.


--
Bryan J. Smith   mailto:b.j.smith at ieee.org